Can transformer

Re-use drinks cans as other things using a purpose-built CNC machine to cut them up.

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Aluminium cans are a useful resource, providing thin sheet aluminium or sometimes steel in a standardised form factor.

The sheets of metal are well protected from damage while the cans are full due to the pressure of the gas inside. This means that the empty cans are almost always either defect free or have only small defects.
To use the sheet material it is necessary to cut the cans up. While this is easy to do maually it is sometimes irritatingly painful. It can also be difficult to neatly perform some actions, like precise shapes or small round holes.
The 'Can Transformer' is actually a small CNC lathe that is designed to use one type of stock: the drinks can. In its current form it uses a rotary tool to cut the can with a 'D' bit. It is controlled by a TinyG GCODE based controller. Cutting patterns are generated using a appropriatetool set (I use LibreCAD and a custom Tcl script that converts DXF to GCODE) in a 2D form, then the GCODEis sent to the MACHINE

This is a drinks can transformer (CanTran).

OK, it's a CNC lathe that has been designed specifically to cut drinks cans into bits. Drinks cans are recycled but they can also be re-used. They are a source of sheet metal which has many uses, the bottoms of the cans can be cut off and made into parts holders, or the entire can can be prforated and used as a lamp or display.

The can transformer been designed to cut standard 330ml cans. It uses a Proxxon rotary tool as a spindle and I use the Duet electronics as a gcode interpreter and stepper driver.
There are some parts that are not 3D printed.

Putting it together
Putting the cantran together is pretty simple.

The frame is two flat plates with holes for 12mm ground rod
Z carriage

Can Top Holder
This part is a bit tricky. There's a thrust bearing that needs to go the correct way round. One hole is larger than the other, this goes in first. The edge of the printed part will need trimming to allow the smaller thrust bearing end to fit. The bearing should rotate freely in the printed part. The 'catch' that engages in the can top hole screws in to the part that holds the thrust bearing. This is so you can change it for different can tops or if it wears out without having to print a whole new top.

An 8mm bolt holds the can top engager, and the MXL gear together. the sequence I used is:
Bolt in top part
M8 washer on bolt
51105 Thrust bearing in top part
M8 45mm bolt (through bearing)
Two M8 Washers on bolt

The MXL belt will have to go on the pulley when it is fitted, it's deliberately a tight fit. The idea is that the thrust bearing is under load as the can rotates.

Parts List

1x NEMA11 Stepper motor
2x NEMA17 Stepper motor
1x M8 Nut
3x M8 washer
1x 51105 thrust bearing (three part)
8x M1.5 countersunk cross head 10mm long screw
1x 93 tooth MXL pulley (I used a part similar to this one, or a derivative:
1x B106MXL MXL belt
3x M3 35mm bolt
2x MXL pulley ( I used Fisher 3D printer pulley from reprap ltd:
1x M8 45mm Bolt
2x 12mm ground rod 170mm long (different lengths give different size machines)
1x M8 60mm Bolt
1x Spring 8mm ID 30mm long
2x M3 35mm bolt
2x LM12UU linear bearing
2x 6mm ground rod 150mm (could be shorter for less Z axis travel)
4x LM6UU linear bearing
6x M3 cross head screws
2x M3 45mm bolt
2x M3 nut
2x small microswitch (Like this:
4x M2.5 countersunk screws
2x M3 countersunk crosshead
1x Flexible coupling 3mm/5mm (
3 to 5mm version)
2x M3 nut
1x M3 threaded rod 150mm long (matches Z axis travel)
1x 500mm MXL cut belt (reprap ltd has this) 6mm wide
4x M3 x 20mm cap head screws
3x 608 bearing
1x M3 45mm bolt
1x M3 nyloc nut
1x M3 45mm hex head bolt
4x Base mounting screws.

I hope I've got everything in there.
Hopefully the photos are enough to go on to put it all together.
If there's more interest then I'll do more detailed instructions


One SCAD file with the 3D printed parts

x-openscad - 24.61 kB - 05/27/2022 at 04:00


  • Calculator Overlays

    menadue06/27/2022 at 14:53 0 comments

    You can see some HP41C overlays I made using the can transformer in this video:

    There's some other materials I tried out as well. 

  • Why not a mini-lathe?

    menadue06/20/2022 at 07:32 0 comments

    When I started using cans as raw materials I did try to mount a can on my mini lathe, and found that it isn't easy to do. It's an awkward shape and then you have the problem of cutting the material.  Hence the work towards making the can transformer. The two key parts to it are the spring loaded mounting (with a shaped part that fits into the drinking hole for rotational grip) and the rotary tool with a d bit for cutting. I thought about making those parts for the mini-lathe, but it was easier and maybe less work to build a dedicated machine to do the work. Trying to find ways to mount things on the lathe would probably have been just as much work, after making a DRO for it.

  • Failures

    menadue06/20/2022 at 07:26 0 comments

    I've detailed all the failed parts I printed when I was developing the transformer:

    They are all in the recycle bin now...

  • Writing

    menadue05/27/2022 at 04:29 0 comments

    Something that is very time consuming is to write on the metal sheet.

    using the can transformer it's pretty easy, just draw text in a CAD tool, convert to gcode and run it through the transformer:

    this application was one of the reasons I made the transformer. I wanted to label some shelves that were outdoors and I thought that cut up cans would make a good weather resistant material to make the labels out of. Cutting cans up was relatively easy, if a bit painful when I got poked by a sharp corner. I then used some number and letter punches to stamp IDs on the labels. That was tedious and the stamped IDs didn't turn out as legible as I'd have hoped, due to the size of the text and the lack of contrast between the stamped letters and the background. Using holes like this has no such problems.

  • Lamps and patterns

    menadue05/27/2022 at 04:24 0 comments

    The can transformer can easily cut patterns in the can like this:

    You can then pop a light source inside and use it as either a lamp or a personalised display like this:

    When cutting a pattern you do have to be careful to use tabs to keep any areas that would otherwise fall out, like the triangular piece in the 'A' above.

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Enjoy this project?



menadue wrote 06/23/2022 at 03:41 point

Ha! I knew there was probably a better name than I had managed to think up!. I thought about 'cantran' but that's a thing already (there is also a cansformer, if you google it, but not as much of a problem, I think). The only thing after cantran was can transformer, but I like cansformer though. :-)

  Are you sure? yes | no

PostalPreacher wrote 06/22/2022 at 16:27 point

So it's a Cansformer?

  Are you sure? yes | no

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